Grand Junction – Federal agents Saturday took over the investigation of a rash of bombs placed outside homes in and around Grand Junction the day before, and have expanded the hunt for the lone suspect nationwide.

Agents for the U.S. Bureau of Alcohol, Tobacco and Firearms obtained a federal warrant Saturday for Robert L. Burke, 54, who also has used the name Robert L. Pope. Burke is a former air-traffic controller who was fired over a personnel matter from his most recent job in Grand Junction in 2004. He previously had worked at airports in three other states.

Agents obtained a search warrant for a Grand Junction storage unit rented by Burke and have been sifting through the items inside for clues to Burke’s background and for possible links to materials used in three bombs that exploded and two others that were detonated by police Friday morning.

“We are in the middle of an extensive manhunt. This is a top priority for the ATF,” said senior ATF agent Kenny Spann of Denver. Spann said be believes Burke acted alone in allegedly making the bombs and placing them at the homes of former co-workers.

All the bombs, which were considered crude but had timers and extra accelerants to increase their fire-starting capability, were placed outside the homes of employees of Serco Group PLC, a company that subcontracts with the Federal Aviation Administration. In Grand Junction, five Serco workers staff the tower at Walker Field Airport.

The bombs scorched siding, melted vinyl and blew off wood trim at two of the homes and caused smoke damage to another.

“We were lucky we didn’t have anyone hurt or killed or have more damage,” said Grand Junction Police Department interim Chief Bill Gardner.

Gardner warned Mesa County residents Saturday to report and not pick up any suspicious looking devices or packages. A bulletin has been posted across the country for Burke’s maroon 1999 Chevrolet Astro van with Colorado license plate 794CYB.

Burke also has worked in California, Arizona and Tennessee. Federal agents are watching airports in those states and determining whether similar bombings or attempted bombings have occurred there. Agents are searching national databases to see if any of thousands of other bombs on file match the components and makeup of the Grand Junction devices.

As of Saturday night, the search had turned up one possible match with an incendiary device detonated last month in Tennessee.

Burke left his last known residence in Grand Junction – an apartment – at the end of 2005, and investigators said they do not know where he has been living since.

“He has been nomadic,” said ATF special agent Tom Mangan of Phoenix. “He moved around quite a bit.”

The first of the Grand Junction bombs – all made in trash cans – exploded at 4:34 a.m. in a usually quiet subdivision, catching the garage door and eaves above the garage on fire at 816 Mazatlan Drive.

The second bomb was discovered by a homeowner at 2256 Knollwood Lane. Bomb-squad detectives detonated that bomb.

At 7:25 a.m., a bomb exploded next to the garage door of a ranch-style home at 2975 Summerbrook Drive. The house was empty, and nobody had been living in it for at least three weeks, neighbors said.

Neighbor Bobby Payton was backing his car out of his garage and leaving for work when the bomb exploded across the street.

“It shot flames to the top of the house,” said Payton, who inspected the remnants of the bomb and described it as a small, metal pail inside a cardboard box. “It wasn’t very loud.”

At 9:42 a.m., a bomb was discovered in the 600 block of Seranade Street. That bomb also was detonated.

A minute later, a bomb exploded at 2344 1/2 Rattlesnake Court.

The bombings brought together a task force of more than 100 law enforcement and civilian personnel from a dozen agencies. Gardner said the investigation will continue as a joint effort under the guidance of the ATF.

Correspondent David Frey and staff writer Manny Gonzales contributed to this report.

Kirk Mitchell is a general assignment reporter at The Denver Post who focuses on criminal justice stories. He began working at the newspaper in 1998, after writing for newspapers in Mesa, Ariz., and Twin Falls, Idaho, and The Associated Press in Salt Lake City. Mitchell first started writing the Cold Case blog in Fall 2007, in part because Colorado has more than 1,400 unsolved homicides.